This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A218790 #12 Mar 28 2014 19:49:45 %S A218790 1,3,5,13,21,37,53,117,181,309,437,693,949,1717,1461,3509,5557,9653, %T A218790 13749,21941,30133,54709,46517,79285,112053,210357,177589,472501, %U A218790 308661,734645,996789,2045365,3093941,5191093,7288245,11482549,15676853,28259765,24065461 %N A218790 a(n) = binary code (shown here in decimal) of the position of the predecessor of the natural number pair (2n,2n+1) in the compact beanstalk-tree A218782. %H A218790 Antti Karttunen, <a href="/A218790/b218790.txt">Table of n, a(n) for n = 1..1024</a> %F A218790 a(n) = A218614(A005187(n)). %o A218790 (Scheme with memoization-macro definec): (definec (A218790 n) (cond ((< n 2) n) ((A011371 (* 2 n)) => (lambda (bp) (if (even? bp) (A004754 (A218790 (/ bp 2))) (A004755 (A218790 (/ (-1+ bp) 2)))))))) %Y A218790 Subset of A218614, i.e. a(n) = A218614(A005187(n)). %Y A218790 Also, a(n) = A054429(A218791(n)). Used to construct A218782, A218783. Cf. also A218787, A218788 %K A218790 nonn,base %O A218790 1,2 %A A218790 _Antti Karttunen_, Nov 16 2012